This invention relates to a fan housing, particularly to a fan housing for allowing air to circulate through a fan having rotating fan blades while serving as a safety guard for the fan and which allows ready access to the fan for cleaning and maintenance.
In the fan industry there is a need for a fan housing which allows a maximum amount of air flow through the fan with a minimum amount of air flow restrictions, while still providing a safety guard which prevents a human hand, finger or similar object from getting into the path of the fan blade. While accomplishing these performance and safety objectives, the fan housing must also allow ready access to the fan unit within the housing for cleaning and maintenance.
A primary concern of the fan industry is safety. During typical fan operation, fan blades are rotated at high RPM's. If an object such as a human hand or finger comes in contact with the rotating blades, the end result may be a severed appendage or even more severe injury. These rotating fan blades are encased within a fan housing in order to limit access to the fan housing during fan operation. It is preferred that these housings be designed to maximize air flow and safety while minimizing air flow restrictions. In order to accomplish these objectives, a fan housing must be designed such that the rapidly rotating fan blade is out of reach of a human hand, finger, or similar object.
Circulating fans are often installed in industrial or agricultural applications which are notoriously unclean environments. In an agricultural application, circulating fans are typically suspended overhead to provide maximum ventilation and air turnover to livestock. In these harsh environments, objects such as hay, straw, dust, chicken feathers, or other airborne material typically become lodged within the fan housing. Therefor, the fan housing must also allow easy access to the fan unit for cleaning and maintenance.
In the past, fans for these applications have had fan guards which include rear and front substantially open fan guard faces (e.g., screens or wire grids), with closed or nearly closed circumferential side walls. Rear and front fan guard faces have been proposed which will permit a hand, finger, or foot to pass partially therethrough. The circumferential side walls connect the rear and front guard faces to enclose the fan blades. The fan blades are spaced approximately equal distances from the front and back guard faces, with the guard faces being far enough away from the fan blades to prohibit a hand, finger, or foot from reaching the fan blade path.
The circumferential walls of these devices have been limited to walls which are totally or essentially closed. The totally closed circumferential walls typically consist of painted or galvanized sheet metal which keeps objects from coming in contact with the fan blade. Other fans of this type have circumferential walls which are essentially closed and typically consist of parallel wires. Although these totally or essentially closed circumferential walls keep the rapidly rotating fan blade out of reach of the human hand, finger, or similar object, the closed nature of these walls inhibits air flow through the fan.
In these typical fan applications, the rear and front guards are fixedly connected to at least a portion of the circumferential walls. To clean and maintain a fan using these fan safety guards, one must unlock the rear and front guards which are secured together via the circumferential wall. Other fans of this type have their fan guard sections bolted or otherwise fixedly secured together so that tools and excessive handling are required to open the fan guard for cleaning and maintenance.